fix: content-type not set with custom domain and accept */*

BREAKING CHANGE

This is a WIP commit and needs discussion. Add description here later

Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>

Author: taimoorzaeem

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file. From versio
 
 ## Unreleased
 
+## Fixed
+
+- WIP, add changelog later.
+
 ## [14.1] - 2025-11-05
 
 ## Fixed

src/PostgREST/ApiRequest.hs

@@ -98,7 +98,7 @@ userApiRequest conf prefs req reqBody = do
   , iMethod = method
   , iSchema = schema
   , iNegotiatedByProfile = negotiatedByProfile
-  , iAcceptMediaType = maybe [MTAny] (map MediaType.decodeMediaType . parseHttpAccept) $ lookupHeader "accept"
+  , iAcceptMediaType = maybe [MTApplicationJSON] (map MediaType.decodeMediaType . parseHttpAccept) $ lookupHeader "accept"
   , iContentMediaType = contentMediaType
   }
   where

src/PostgREST/Plan.hs

@@ -1140,9 +1140,10 @@ negotiateContent conf ApiRequest{iAction=act, iPreferences=Preferences{preferRep
       x                                           -> lookupHandler x
     mtPlanToNothing x = if configDbPlanEnabled conf then x else Nothing -- don't find anything if the plan media type is not allowed
     lookupHandler mt =
-      when' defaultSelect (HM.lookup (RelId identifier, MTAny) produces) <|> -- lookup for identifier and `*/*`
-      when' defaultSelect (HM.lookup (RelId identifier, mt) produces) <|>    -- lookup for identifier and a particular media type
-      HM.lookup (RelAnyElement, mt) produces                                    -- lookup for anyelement and a particular media type
+      when' defaultSelect (HM.lookup (RelId identifier, mt)    produces) <|>  -- lookup for identifier and a particular media type
+                           HM.lookup (RelAnyElement   , mt)    produces  <|>  -- lookup for anyelement and a particular media type
+      when' defaultSelect (HM.lookup (RelId identifier, MTAny) produces)      -- lookup for identifier and */* media type
+
     when' :: Bool -> Maybe a -> Maybe a
     when' True (Just a) = Just a
     when' _ _           = Nothing

src/PostgREST/SchemaCache.hs

@@ -1078,17 +1078,45 @@ mediaHandlers =
         proc.pronamespace = ANY($$1::regnamespace[]) and NOT proretset
         and prokind = 'f'|]
 
+-- We take the union of two maps:
+-- First map builds the mapping of domain types -> resolved media type
+-- Second map creates the same mapping, but with "*/*" key
+-- Example:
+-- +------------------------------------------------+
+-- |    domain type    |     resolved media type    |
+-- +------------------------------------------------+
+-- |    text/plain     |        text/plain          |
+-- +------------------------------------------------+
+-- |       */*         |        text/plain          |
+-- +------------------------------------------------+
+-- This allows us to resolve to "text/plain" on both
+--  "Accept: text/plain" and
+--  "Accept: */*"
+--
+-- TODO: This basically doubles the size of the map, so we should do some
+--       production scale memory tests to make sure with aren't hitting OOM errors
 decodeMediaHandlers :: HD.Result MediaHandlerMap
-decodeMediaHandlers =
-  HM.fromList . fmap (\(x, y, z, w) ->
-    let rel = if isAnyElement y then RelAnyElement else RelId y
-    in ((rel, z), (CustomFunc x rel, w)) ) <$> HD.rowList caggRow
-  where
-    caggRow = (,,,)
-              <$> (QualifiedIdentifier <$> column HD.text <*> column HD.text)
-              <*> (QualifiedIdentifier <$> column HD.text <*> column HD.text)
-              <*> (MediaType.decodeMediaType . encodeUtf8 <$> column HD.text)
-              <*> (MediaType.decodeMediaType . encodeUtf8 <$> column HD.text)
+decodeMediaHandlers = mapFromList <$> HD.rowList caggRow
+    where
+      mapFromList aggRowList =
+        HM.union
+          (HM.fromList . fmap (aggRowToList False) $ aggRowList) -- type -> type map
+          (HM.fromList . fmap (aggRowToList True) $ aggRowList)  --  */* -> type map
+
+      caggRow = (,,,)
+                <$> (QualifiedIdentifier <$> column HD.text <*> column HD.text)
+                <*> (QualifiedIdentifier <$> column HD.text <*> column HD.text)
+                <*> (MediaType.decodeMediaType . encodeUtf8 <$> column HD.text)
+                <*> (MediaType.decodeMediaType . encodeUtf8 <$> column HD.text)
+
+      aggRowToList withMTAny (x,y,z,w) = ((rel, mt), (CustomFunc x rel, w))
+        where
+          -- we don't add the */* mapping when rel is "anyelement" because we
+          -- already have (RelAnyElement, MTAny) in the initial media handler
+          -- map which maps to "application/json"
+          mt = if withMTAny && (rel /= RelAnyElement) then MediaType.MTAny else z
+          rel = if isAnyElement y then RelAnyElement else RelId y
+
 
 timezones :: Bool -> SQL.Statement () TimezoneNames
 timezones = SQL.Statement sql HE.noParams decodeTimezones

test/spec/Feature/Query/CustomMediaSpec.hs

@@ -116,6 +116,16 @@ spec = describe "custom media types" $ do
         , matchHeaders = ["Content-Type" <:> "text/xml; charset=utf-8"]
         }
 
+    it "should get the return type of function when accept is */*" $ do
+      request methodGet "/rpc/javascript"
+        [("Accept", "*/*")]
+        ""
+        `shouldRespondWith`
+        "This is Javascript."
+        { matchStatus = 200
+        , matchHeaders = ["Content-Type" <:> "text/javascript"]
+        }
+
     it "should fail with function returning text and Accept: text/xml" $ do
       request methodGet "/rpc/welcome" (acceptHdrs "text/xml") ""
         `shouldRespondWith`

test/spec/fixtures/schema.sql

@@ -107,7 +107,7 @@ SET search_path = test, pg_catalog;
 SET default_tablespace = '';
 
 SET default_with_oids = false;
-
+create domain "text/javascript" as text;
 create domain "text/plain" as text;
 create domain "text/html" as text;
 create domain "text/xml" as pg_catalog.xml;
@@ -1884,6 +1884,10 @@ create or replace function welcome() returns "text/plain" as $$
 select 'Welcome to PostgREST'::"text/plain";
 $$ language sql;
 
+create or replace function javascript() returns "text/javascript" as $$
+select 'This is Javascript.'::"text/javascript";
+$$ language sql;
+
 create or replace function welcome_twice() returns setof "text/plain" as $$
 select 'Welcome to PostgREST'
 union all